Thread protector for use during running of tubular elements into an oilwell



June 12, 1962 E. D. HAUK ETAL 3,038,502 THREAD PROTECTOR FOR USE DURING RUNNING OF TUBULAR ELEMENTS INTO AN OILWELL Filed Sept. 15, 1958 3 Sheets-Sheet 1 12 ,6 [1/55 7D. 1270K foamy/l1. Dear IN V EN TORS June 12, 1962 E. D. HAUK ETAL 3,038,502 THREAD PROTECTOR FOR USE DURING RUNNING OF TUBULAR ELEMENTS INTO AN OILWELL 3 Sheets-Sheet 2 Filed Sept. 15, 1958 Julie 12, 1962 UK ETAL 3,038,502

THREAD PROTECTOR FOR USE DURING RUNNING OF TUBULA ILWE United States Patent Oil 3,038,502 Patented June 12, 1962' THREAD PROTECTDR FOR USE DURING RUN- NINIE OF TUBULAR ELEMENTS INTO AN OIL- WE Ernest I). Hank, Long Beach, and Hobart M. Turley,

Oak View, Calif., assignors to Klampon Thread Protector, Signal Hill, Calif., a corporation of California Filed Sept. 15, 1958, Ser. No. 761,261 14 (Ilaims. (Cl. 138--96) This invention relates to a thread protector, and more particularly to a device for protecting the threads on the end of a section of oil well casing while such end is dragged along the walk leading to an oil well prior to introduction of the casing section into the well hole. The application constitutes a continuation-in-part of co-pending application Serial No. 584,952, filed May 15, 1956, now abandoned, inventor Hobart M. Turley.

In drilling oil wells, it is conventional practice to feed each section of well casing into the well in the following manner. One end of a generally horizontal casing section is first connected to a cable from the derrick over the well, and such cable is employed to drag the casing section to the well and then to lift and tilt the section to a vertical position over the hole. The end of the section which is not connected to the cable is, during the initial stages of the operation, dragged along the walk leading to the well, and at a relatively rapid rate. It will be apparent that some means must be provided to protect the threads on the casing end thus dragged, or they will be severely damaged. Such means are applied after removal of the protectors employed during shipping of the casing sections, since such shipping protectors are substantially worthless for the present purpose.

Conventional thread protectors for the above purpose are generally of an all metal type requiring an excessive amount of time for application, and also for removal before the section is actually lowered into the hole. Such protectors are easily broken, and have the additional disadvantage that no protection is afforded to the operators, who are sometimes struck by the rapidly moving casing end. In relatively recent times such all metal thread protectors have been partially supplanted by a resilient type which is inflated by air pressure in order to effect mounting thereof over the casing end. This inflatable protector has, however, the disadvantages of relatively high cost and short life. In addition, a special air pressure source must be provided for the inflating operation, and it is conventional practice to require a special operator just to manipulate the thread protector.

Another highly important defect of conventional thread protectors is that a single protector may only be used on one type and size of pipe or casing thread. Thus, it is a frequent occurrence that different shapes and sizes of protectors must be employed in drilling the same well, since different types of threads are employed at different depths in the well. In addition, there is no thread protector known to applicants which operates satisfactorily on the steep threads of drill pipe sections.

In view of the above factors characteristic of thread protectors for oil well casing sections and the like, it is an object of the present invention to provide a simple and economical, yet extremely rugged and effective, thread protector which may be used without special operators or air pressure sources and which is adapted to protect not only the threads but also the operators who may be struck by the rapidly moving end of the casing section.

Another object of the invention is to provide a thread protector incorporating a quick-acting locking and unlocking means which may be operated by relatively unskilled labor, such locking means being buried in rubber for prevention of injury thereto or to the operators.

An additional object of the invention is to provide a thread protector embodying combination locking means and return means, the latter serving to facilitate moving of the thread protector from the well head to the station at which the protector is mounted on the next section of casing.

A further object is to provide a thread protector in which the only exposed outer parts are formed of relatively thick rubber adapted to protect operators and equipment frequently struck by the rapidly moving casing section end, the latch or locking means being buried or recessed into the rubber so that there is no possibility that these means will create injury or will themselves be damaged.

A further object is to provide a single thread protector which will operate satisfactorily on different types of threads conventionally employed in oil well drilling operations, conversion from one type of thread to another requiring only a simple adjustment.

These and other objects and advantages of the invention will be more fully set forth in the following specification and claims, which are to be considered in connection with the attached drawings to which they relate.

In the drawings:

FIGURE 1 is an isometric view illustrating a thread protector, constructed in accordance with the present invention, in mounted and locked condition on the externally threaded end of a casing section;

FIGURE 2 is a partial transverse sectional view taken along line 2-2 of FIGURE 1, but illustrating the mounting or locking means in open or unlocked condition as distinguished from the closed or locked condition shown in FIGURE 1;

FIGURE 3 is a plan View showing the thread protector in closed or locked condition, looking from the top in FIGURE 1;

FIGURE 4 is a side view showing the thread protector as mounted on a trolley or return wire;

FIGURE 5 is a transverse sectional view taken on line 55 of FIGURE 3;

FIGURE 6 is an exploded isometric view of the cam portion of the locking or mounting means;

FIGURE 7 is an isometric view showing a modified form of the invention in mounted and locked position on the externally threaded end of a casing section;

FIGURE 8 is an exploded isometric view of the locking arrangement for the metal cylinder within the rubber casing or body;

FIGURE 9 is a partial transverse sectional view illustrating the connection of the locking means with the ends of the metal cylinder within the body;

FIGURE 10 is a section view taken along line 1010 of FIGURE 9, showing the trunnion mounting arrangement for the cam sleeve;

FIGURE 11 is a fragmentary sectional view showing the modification of FIGURES 7-10 as associated with a casing having steeply tapering threads, the number of threads being reduced for purposes of clarity or" illustration;

FIGURE 12 is a view similar to FIGURE 11 with the body in locked position on the casing end, showing the threaded engagement of the body with the casing threads;

FIGURES l3 and 14 are views similar to FIGURES 11 and 12 but illustrating the clamping attachment of the body to casings having threads of shallow taper; and

FIGURES 15 and 16 are views similar to FIGURES l1 and 12 but showing the engagement with casings having step threaded ends.

Referring to the drawings, the thread protector of the invention is illustrated in FIGURES 1 and 3 as mounted on the externally threaded tapered end 10 of a section 11 of oil well casing. Stated generally, the thread protector comprises a split annular body 12, and quick-acting locking or latch means 13 to alternately reduce and increase the diameter of body 12 and thus effect, respectively, mounting and demounting of the body from casing end 10. The locking means 13 includes a trolley or roller portion 14 which is adapted to be mounted on a return wire 16 (FIGURE 4) so as to facilitate movement of the thread protector, after its demounting from casing end 10, from the well head to a point of application to the next casing section.

Body 12 of the thread protector is formed of rubber, or other suitable elastomeric or plastic material, having embedded therein a split metal ring or cylinder 17, the latter preferably being formed of a suitable resilient steel. Metal cylinder 17 the split in which corresponds in location to the split or gap in the rubber portion of body 12, is molded into the rubber at a point radially adjacent the threads of casing end 10. Accordingly, only a relatively thin section 18 of rubber is formed inwardly of metal cylinder 17, and the main body of rubber (outwardly of cylinder 17) is formed as a thick section 19 having several times the thickness of section 18. As shown in FIGURE 5, metal cylinder 17 is somewhat narrower than the rubber body in which it is embedded, so that the edges of the cylinder are protected and concealed by the edge portions of the thin and thick rubber sections 18 and 19.

Resilient ring or cylinder 17 has a natural set such that it causes the body 12 to tend to increase in diameter to a diameter greater than that permitted by locking means 13. This operates, as will be described subsequently, to maintain trolley 14 stable when locking means 13 is in the open or unlocked position shown in FIGURES 2 and 4.

The thin body section 18 has a tapered or frustoconical inner wall 21 adapted to be pressed tightly against the threads of casing end 10 upon operation of locking means 13 to reduce the diameter of the body. Section 18 is sufiiciently thin that the radial forces created when metal cylinder 17 is reduced in diameter will be transmitted radially inwardly in an eflicient manner, to create a strong gripping action between thin section 18 and the threads. Such gripping action insures that the thread protector may not he slid oif the section end 10 despite the extremely rough treatment which occurs when it is dragged along the walk.

The thick rubber section 19 has a generally cylindrical outer wall but is suitably beveled at both ends so as to minimize the possibility that the body 12 will catch on any obstructions in its path of movement. A radially inwardly extending flange 22 is formed integral with the outer end of body 12 and is adapted to abut the extreme end edge of the casing section, and thus serve as a stop. The flange 22 has a section cut out therefrom, as seen at 23 in FIGURES 1 and 2, in order to permit movement of the trolley portion 14- to a position inside the casing when the locking means 13 is shifted to the locking position shown in FIGURES 1 and 3.

Proceeding next to a description of the locking or latch means 13, a generally rectangular recess 26 is formed in thick rubber portion or section 19 on opposite sides of the gap in body 12, the recess extending clear to the metal cylinder 17. As best shown in FIGURE 5, a pair of trunnion blocks 27 are rigidly mounted on cylinder 17, at one side of the gap or split, by means of cap screws 28. The heads of the cap screws, which extend radially outwardly through cylinder 17 and into the blocks 27, are recessed into thin rubber section 18 in order that they will not come into engagement with the threads of casing end 10. The trunnion blocks 27 shown in FIGURE receive trunnions '29 which are fixedly secured to a journal block 31, the latter having an opening 32 formed therethrough transverse to the trnnnions. A cylindrical cam actuator element 33 is rotatably mounted in opening 32 and is secured in position by means of a pair of nuts 34 threaded onto one end thereof. It is pointed out that recess 26 communicates with a transverse recess 36 (FIGURES 2 and 3) which is adapted to facilitate mounting and adjusting of the nuts 34 and associated parts. The nuts 34 may be adjusted to determine the tightness of body 12 on the threads.

The cam actuator element 33 extends in a plane perpendicular to the axis of body 12 across the gap in such body and into a cam sleeve 37 best shown in FIGURE 6. The cam sleeve is provided with trunnions 38 which are pivoted in trunnion blocks 39, corresponding to the trunnion blocks 27 previously described, and secured in position on the remaining end of cylinder 17 by screws 41. The cam sleeve is formed with two cam slots 42 and 43 each of which is adapted to receive one projecting end of a cam actuator or cross pin 44 which is fixed transversely through the end of element 33.

Each cam slot 42 and 43 is formed with a portion, relatively adjacent the gap in body 12, which has a steep inclination relative to the axis of the body. This steep portion merges with a portion relatively remote from the gap, and which is at only a slight angle relative to such axis. Since each cam slot 42 and 43 extends correspondingly for about sleeve 37, it follows that a 180 rotation of cam actuator element 33 will eflect shifting of the ends of cross pin 44 from the steeply inclined ends of their slots 42 and 43 (adjacent the gap) to the gently inclined ends thereof (remote from the gap). This movement effects longitudinal shifting of cam sleeve 37 on cam actuator element 33 to either narrow or widen the gap in body 12, depending on the direction of rotation of the cam actuator element.

A bell crank element 46 is welded at one end to cam actuator 33 at a point between journal block 31 and cam sleeve 37, and is provided at its other end with a cross handle 47. The relative rotated positions of cam actuator pin 44 and bell crank 46 are such that the free end of the bell crank will be inside the body 12 when pin 44 is at the ends of slots 42 and 43 remote from the gap, that is to say when the locking or latching means is closed as shown in FIGURES l and 3. Upon rotation of the bell crank 180 to the position shown in FIGURES 2 and 4, at which cam actuator pin 44 is at the ends of slots 42 and 43 adjacent the gap in body 12, the free end of the bell crank extends radially outwardly as illustrated. In both of its extreme positions, which are governed by the ends of slots 42 and 43 which act as stops, the free end of the bell crank lies generally in a plane perpendicular to the axis of the body 12. It is pointed out that flange 22 has sufficient thickness to insure that the outer portion of hell crank 46 will not be exposed when locking means 13 is closed (FIGURES 1 and 2).

The trolley or roller portion 14 of locking means 13 comprises a V-plate 51 which is pivotably connected by a pin 52 to an arm 53 extending from the free end portion of bell crank lever 46. A pair of sheaves or rollers 54 are mounted on the plate 51, on opposite sides of pin 52, and are freely rotatable so that trolley portion 14 may roll along the wire 16. It is to be understood that wire 16 is strung between the well head and the point where the thread protector is applied onto a'pipe section, and is inclined so that the thread protector will slide along the wire 16 at a relatively rapid rate.

Arm 53 lies on the same side of the outer bell crank portion as the inner bell crank portion. Accordingly, trolley 14 is disposed directly above body 12 for good balance and trolley action when the locking means 13 are open (FIGURES 2 and 4), yet is desirably concealed inside the body when the locking means are closed.

In the operation of the thread protector of the invention, let it first be assumed that the locking means 13 are in the unlocked position shown in FIGURES 2 and 4, the free end of hell crank 46 then extending radially outwardly as illustrated. The cam actuator or cross pin 44 is then in the ends of cam slots 42 and 43 which are adjacent the gap in body 12, and is held in such ends by the resilience of metal cylinder 17 which, as stated previously, tends to assume a larger diameter condition. Since the ends of cross pin 44 tend to remain in the inner slot ends, adjacent the gap in body 12, it follows that bell crank 46will be held in its illustrated position and will not pivot or flop back and forth in a manner such as would impede operation of trolley means 14.

In order to mount the thread protector on a casing section end at a point spaced a substantial distance from the well head, it is merely necessary to position body 12 around the end 10 and then rotate bell crank 46 180 from its outer position to the inner position shown in FIGURES l and 3. The initial portion of this bell crank rotation operates, against the bias exerted by metal ring 17, to decrease the width of the gap in body 12 at a relatively rapid rate due to the above-described steep inclination of the portions of cam slots 42 and 43 which are adjacent the gap. The body 12 is thus reduced in diameter at a rapid rate and comes into engagement, at tapered inner wall 21, with the threads of casing end 10. Continued rotation of bell crank 46 after such initial thread engagement results in further reduction in the diameter of body 12, but at a slower rate and with a much greater mechanical advantage due to the fact that the ends of slots 42 and 43 remote from the gap are only gently inclined as previously stated. A very tight thread gripping action is thus achieved with a minimum of power required to rotate bell crank 46, which insures that the body 12 will not move 01f the casing end 10 despite the extreme abuse to which the protector is subjected as the casing end is dragged along the walk toward the well head. It is to be understood that the locking means 13 will remain in closed condition due to the presence of notches 56 at the outer ends of the cam slots.

It is emphasized that the bell crank 46 and trolley 14, and all other parts of locking means 13, are completely recessed in recesses 26 and 36, or in the gap between the ends of the body and flange, so'that they cannot come into engagement with drilling operators or drilling equipment and effect injury to either. The construction of the body 12 with the thick outer section 19 formed of rubber, and with the beveled edges, also means that contact between the thread protector and operators or equipment will result in a minimum of injury and damage.

After the casing section has been lifted to vertical position over the well hole, it is merely necessary for the operator to grasp the handle 47 and rotate it 180 to the position shown in FIGURE 2, the body 12 then springing to a larger diameter so that it drops off the section end. The last portion of such rotation is effected automatically, and with a snapping action, due to the outward bias exerted by cylinder 17 which operates through cam 37 to rotate cam actuator element 33 and thus the bell crank until the pin 44 engages the inner ends of the cam slots. The operator may then, without releasing his grip on handle 47, mount trolley portion 14 on Wire 16 and thus rapidly return the thread protector to its original location.

Embodiment of FIGURES 7-16 A modified form of the invention may be seen in FIG- URES 7 through 16 wherein the locking arrangement is shown as substantially completely buried in rubber. In addition, a dual taper and threaded portion are imparted to the interior surface of the body for reasons which will be set forth hereinafter.

Body 56 is similar in design to body 12 previously described, being formed of a suitable shock absorbing material, such as rubber or soft plastic. Annular metal ring or cylinder 57 is buried in the body and provided with end brackets 58 and 59 attached thereto by rivets 60 and 61. Brackets 58 and 559 include pairs of parallel side plates 62 and 63 communicating with interiorly threaded sleeves 65 and 66 forming trunnion supports for the locking means.

Pairs of trunnion screws 67 and 68 are threadably received in sleeves 65 and 66, the inner unthreaded ends 69 and 70 of these screws extending into journal block 72 and cam sleeve 73. Suitable lockwashers, not shown, are provided beneath the heads of the trunnion screws.

Cam actuator 74 is received within journal block 72 and cam sleeve 73, being rotatable relative thereto. One end of actuator 74 is retained to the journal block by a self-locking or thread-gripping nut 75. The opposite end of the cam actuator includes pin 76 extending radially into slots 77 and 78 in the cam sleeve. This portion of the locking arrangement is similar to the actuator and sleeve arrangement of the previously described embodiment. Hence, slots 77 and 78 are shaped similarly to slots 42 and 43, so that rotation of actuator 74, through pin 76, imparts linear movement to the ends of the cylindrical member 57, either drawing end brackets 58 and 59 towards each other or allowing them to separate under the spring force provided by the resilience and outward set of cylinder 57. Thus, when actuator 74 is rotated by crank 80 to the position of FIGURES 7 through 10, the body will be firmly mounted on the threaded end of casing or pipe 11. In this clamped position, free end 81 of the crank extends inwardly with respect to body 56 at the end of the pipe. Rotation of end 81 through 180 to a radially extended position, similar to that shown for end 46 in FIGURE 4, loosens the body and permits hook 83 to engage Wire 16 (FIGURE 4) for returning the thread protector.

It is emphasized that in this embodiment all elements of the locking arrangement are fully buried or suspended within the resilient body member. This means that the body can perform its protective function without danger of damage to the well casing end, the thread protector itself, or the person operating the device. The suspension of the locking arrangement in rubber is highly important since it permits the lock to ride with each blow imparted thereto, so that no damage results.

Adjustment of the diameter of the metal cylinder 57, when in locked position, is achieved by rotation of self locking nut 75. Access to this nut is obtained through body aperture 85 which is only slightly larger than the nut and permits entry of a socket wrench 86 which is rotated by T-handle 87. When nut 75 is tightened, end brackets 58 and 59 are drawn closer together in the locked position, whereby the interior of the body is given a greater reduction in size. This not only permits adjustment of the clamping force exerted by the body, but also permits use of the thread protector on pipe or casing ends of various types and sizes.

Referring now to FIGURE 10, it may be seen that inner surface 90 of body 56 is provided with dual sections 91 and 92 of frusto-conical form, tapering or converging toward end flange 93. Section 91 is of a relatively shallow taper, while section 92, farther away from end flange 93, is of a relatively steeper taper. In addition, section 92 includes inwardly projecting threads 94.

This construction of the interior of the body is important it that it permits use of a single thread protector with equal effectiveness on various conventional types of threaded casing ends, as seen in FIGURES 11 through 16. In FIGURE 11, the body 56 is shown in the unclamped position over end 10a of casing 11a, threads $6 of which taper relatively sharply toward the end of the casing and are known as extreme line threads. When the body is clamped on the end of this section (FIGURE 12), relatively steeply tapering portion 92 thereof is substantially complementary to the tapering casing end, and will threadedly engage the casing with a firm grip. Threads 94 of section 92 mesh with threads 96 of the casing so that, despite the steep taper of casing end 1%, the body will not be inadvertently dislodged from the casing. Section 91 of relatively shallow taper makes no gripping engagement with the threads 96, but this is of no consequence in view of the firm gripping engagement between threads 94 and 96. The principle of this embodiment may be applied to the steep threads of drill pipe, etc.

In FIGURES l3 and 14, the thread protector may be seen as applied to end b of a different type of casing, numbered 11b, having relatively shallow tapering threads 97. Threads 97 are of the standard API (American Petroleum Institute) type. For this type of arrangement, relatively shallow taper portion 91 i substantially complementary to the taper of threads 97 and when the body is clamped on, as seen in FIGURE 14, section 91 firmly grips the outer thread section, becoming embedded therein. Relatively steeply tapering portion 92 does not grip the threads 97 to any appreciable extent, but the tight gripping engagement between section 91 and the threads assures that the protector is firmly clamped on the end of the casing. Should the protector start to come off while the casing is being dragged in, it binds and will remain in protective condition on the casing.

In FIGURES and 16, the protector is illustrated with still a different type of casing end, of step threaded construction, having an outer threaded section 98 of a relatively small diameter and inner section 99 of larger diameter. No taper is provided on casings of step threaded construction. When the body is clamped on the step threads, as seen in FIGURE 16, the dual tapered form of the interior of the body means that the body will grip threads 98 and 99 at the inner end of each taper as indicated at 100 and 101. Thus again, despite a considerably dilferent contour for the end of the well casing, the protector will provide a tight grip which will preclude its becoming dislodged during handling of the casing.

It can be seen by the foregoing, therefore, that the protector is of relatively universal applicability, which by provision of the dual taper will accommodate all types of well casing ends commonly encountered. This is regardless of whether the threads are steep or shallow taper, or whether any taper at all is provided.

Furthermore, the adjustment for the locking device assures that proper clamping force can be readily obtained, and also means that by a simple adjustment of nut 75 the protector will fit on casings of diiferent diameters. The adjustment of nut 75 by wrench 86 acts in combination with the dual clamp and thread means 91 and 92 to provide protection of casings having the same diameter but different types of threads. Thus, and although the casing diameter is the same, the thread circumference of API casing (FIGURES 13 and 14) at the contact area may be approximately inch greater than that of extreme line casing (FIGURES 11 and 12). To change to extreme line from API, therefore, it is merely necessary to tighten nut 75 with wrench 86. As previously indicated, the protector fits on extreme line thread by a threading or meshing action (FIGURE 12), and fits on API and Step threads by a clamping action (:FIGURES 14 and 16).

As a specific example of the dual threaded and unthreaded sections 91 and 92 of the rubber body 56, section 91 may have a taper of about 2 degrees relative to the axis, and section 92 may have a taper of about 3 /2. degrees relative thereto. For 6% inch casing, section 92 may be 2 inches long, section 91 may be 1% inches long, and the diameter at the wide end of section 92 may be about 6.59 inches. Section 92 may have 14 threads each having a width of about .06 inch and a height of about .04 inch.

Various embodiments of the present invention, in addition to what has been illustrated and described in detail, may be employed without departing from the scope of the accompanying claims.

We claim:

1. A protector for the external threads at one end of a section of oil well casing or the like, which comprises a relatively thick annular body formed of elastomeric material, said body having a gap or split at one point about the circumference thereof, a resilient metal band embedded in said body and having a corresponding gap or split, said band being continuous except at said gap or split, and locking means connected between the ends of said metal band to reduce the diameter of said band and body and thus clamp said body on the threads at said section end, said locking means being of a quick-acting type and being spaced radially-inwardly from the outer surface of said body.

2. A thread protector for exterior threads at the end of a pipe section, which comprises a generally cylindrical resilient metal ring having a transverse split or gap at one point about the circumference thereof, an elastomeric body molded around said ring and having a corresponding transverse split, said body having a relatively thin section radially inwardly of said ring and shaped to grip against the threads on said pipe, said body also having a thick section radially outwardly of said ring, and locking means disposed in a recess in said thick section and connected across said split or gap between the ends of said ring, said locking means being adapted to alternately re duce and increase the diameter of said ring and thus of said body.

3. The invention as claimed in claim 2, in which said locking means comprises cooperating cam and cam actuator elements adapted when rotated relative to each other to move the ends of said ring toward or away from each other.

4. The invention as claimed in claim 2, in which a flange is formed on said body and extends radially inwardly for stopping abutment with the end of said pipe section.

5. A protective device for a cylindrical member having exterior threads on one end thereof, comprising a thick and substantially annular body of elastomeric material adapted to fit around the threads of such cylindrical member, a substantially annular metal member disposed within said body, and lock means connected to said metal member for reducing the interior diameter of said metal member and effecting clamping of said body and metal member on said threads, said lock means being spaced radially inwardly from the exterior surface of said body for protection thereby, the interior surface of said body having a duality of sections which taper convergently toward one end of said body and are adapted to engage the threads of various types of cylindrical members, one of said sections being of a relatively shallow taper and the other of said sections being of a relatively steep taper, said last-mentioned section being provided with thread means therein.

6. A protective device for a cylindrical member having exterior threads on one end thereof, comprising a thick annular body of shock absorbing material adapted to fit over the threads of such a member, said body having a transversely extending split therein for permitting a reduction in diameter thereof, a metal band embedded within said body, said band having a corresponding split therein, clamping means connected between the ends of said band at said split therein for urging the ends of said band at said split toward each other to thereby exert a force for clamping the interior surface of said body on such cylindrical member and attaching said body thereto, said clamping means being recessed into said body, said interior surface having a duality of sections tapering inwardly toward one end of said body for enabling said body to be clamped on threads of various contours, one of said sections being of a relatively steep taper and the other of said sections being of a relatively shallow taper, said section of relatively steep taper having threads projecting inwardly therefrom for meshing with threads on certain cylindrical members with which said body is adapted to be associated.

7. A thread protector for the exterior threads at the ends of tubular oilwell equipment, which comprises a thick annular element formed of elastomeric material and having a split at only one point therein, a resilient ring formed of metal and buried or embedded in said elastomeric element, said metal ring having a single split corresponding in location to that of said elastomeric element, locking means substantially completely buried in said elastomeric element and connecting the ends of said metal ring at said split therein, said locking means being adapted to reduce and increase the diameter of said metal ring and thus of said elastomeric element, and means effecting access to said locking means through a portion of said elastomeric element in order to permit adjustment of said locking means and thus of the diameter of said metal ring when in closed condition.

8. A thread protector for use during the running of oil well casing into a well; which comprises a thick annular body formed of elastomeric material and having a split at only one point therein, said body having an interior thread-engaging wall coaxial therewith and having a radially-inwardly extending stop flange at one end thereof, said wall being formed with two generally frustoconical sections both of which diverge away from said flange, the frustoconical section adjacent said flange being relatively shallowly tapered and being relatively smooth-walled, the frustoconical section remote from said flange merging with said adjacent section and being relatively steeply tapered, said steeply tapered section having inwardly extending thread means adapted to mesh with certain types of casing threads; a hollow resilient metal cylinder embedded in said thick elastomeric body and spaced radiallyoutwardly from said interior wall a substantial distance which is less than the inward spacing thereof from the outer wall of said body, said cylinder having a gap therein corresponding to said split; and lock means substantially completely embedded in said body and connecting the ends of said metal cylinder at said gap, said lock means comprising a cam actuator rod rotatably associated with one end of said metal cylinder on one side of said gap, a cam sleeve mounted around said cam actuator rod and connected to the other end of said metal cylinder on the other side of said gap, cam follower means associated with said rod and riding in a cam slot in said cam sleeve, said cam slot having a steep section relatively adjacent said one end of said metal cylinder and a gently inclined section relatively remote from said one end thereof, a crank mounted on said cam actuator rod and adapted to rotate the same through substantially 180, said crank being mounted between the ends of said body at said split therein and being movable from an outwardly-radially extending position to an inwardly-radially extending position.

9. A thread protector, comprising a thick annular body formed of elastomeric or plastic material and adapted to engage the exterior threads on the tapered end of a tubular element, said body having an interior wall tapering in general correspondence with said tapered end, thread means provided interiorly on said wall for meshing with said threads on said tapered end, and means to reduce and increase the diameter of said body to effect meshing and unmeshing of said thread means relative to said threads, said reducing and increasing means being disposed radially inwardly from the exterior wall of said body.

10. A thread protector for exterior threads at the end of a pipe section, which comprises a generally cylindrical resilient metal ring having a transverse split or gap at one point about the circumference thereof, an elastomeric body molded around said ring and having a corresponding transverse split, said body having a relatively thin section radially inwardly of said ring and shaped to grip against the threads on said pipe, said body also having a thick section radially outwardly of said ring, and locking means disposed in a recess in said thick section and connected across said split or gap between the ends of said ring, said locking means comprising a cam actuator rod rotatably connected to one end of said ring and extending across said gap, a cam sleeve mounted around said cam actuator rod and connected to the other end of said ring, and a projection provided on said rod and riding in a slot in said sleeve, said slot having a steep section relatively adjacent said gap and a gently inclined section relatively remote from said gap, said locking means being adapted to alternately reduce and increase the diameter of said ring and thus of said body.

11. The invention as claimed in claim 10, in which a hell crank is connected to said rod and is movable between a radially outwardly extending position at which said projection is in said steep section, and a radially inwardly extending position at which said projection is in said gently inclined section.

12. A thread protector for protecting exterior threads at the end of a section of oil well pipe immediately prior to running thereof into an oil well, which comprises a thick annular body formed of elastomeric material and having a gap therein; an annular strengthening element disposed within said body coaxially thereof and having a correspondingly located gap therein; and quick-acting cam means connected between the ends of said strengthening element at the gap therein and operable to move said ends together and apart for clamping of said body and strengthening element on said threads and releasing of said body and strengthening element therefrom, said cam means being recessed into said body, said cam means comprising a cam element disposed at said gaps and having slot means therein, and means mounted in said slot means and responsive to movement relative to said cam element to effect said clamping and releasing movement of said ends.

13. The invention as claimed in claim 12, in which crank means are provided to eifect said relative movement .between said cam element and said last-named means, said crank means being disposed radially inwardly from the exterior surface of said body when said ends are relatively adjacent each other and said body and strengthening element are clamped on said threads, said crank means extending radially outwardly from said body when said ends are relatively remote from each other and said body and strengthening element are released from said threads.

14. A thread protector for protecting exterior threads at the end of a section of oil well pipe immediately prior to running thereof into an oil well, which comprises a thick annular body formed of elastomeric material and having a gap therein; an annular strengthening element disposed within said body coaxially thereof and having a correspondingly located gap therein; and quick-acting means connected between the ends of said strengthening element at the gap therein and operable to move said ends together and apart for clamping of said body and strengthening element on said threads and releasing of said body and strengthening element therefrom, said last-named means being recessed into said body for protection thereby.

References Cited in the file of this patent UNITED STATES PATENTS Re. 18,184 Brown et a1 Sept. 8, 1931 1,498,563 Morrison et al. June 24, 1924 1,862,858 Lyon June 14, 1932 2,215,251 Prince Sept. 17, 1940 2,518,981 Edwards Aug. 15, 1950 2,523,930 Unke Sept. 26, 1950 2,747,617 Walden May 29, 1956 2,824,579 Groh et al Feb. 25, 1958 

